Kenmore (Whirlpool) 1979, belt-driven, 110.82082110, jams up, won't do anything but fill.

[Whirly]

I have a Kenmore Whirlpool from 1979, belt-driven, no electronics,  110.82082110  Never gave me any trouble except the belt had to be tightened once

Now it jams suddenly and won't do anything but fill.

I had just done a full load, was running on load 2, I heard a squeak for 3 or 4 seconds, then everything but the motor stopped.   Drum would not turn/move at all even by hand.

Viewed from behind, the motor turned but the belt didn't move.   While unplugged, I moved it by hand and at first it almost took two hands.  It got easier in two steps until it was very easy. 

I turned it on and it ran for two minutes, then I heard a CLINK and immediately the belt stopped again.

Pushed it by hand again, this time it got easy faster.  Turned it on, put it in the spin section as well as the agitate section of the cycle.  I ran it for 3 minutes and turned it off.

It worked well but I didn't do anything and I'm sure the problem is not solved. 

The wig-wag solenoids seem okay, the rods inside move.  I've looked at everything, don't see anything that is broken, but I don't know what to look for.       TIA.

[Vance R]

Loosen the belt and check the pump, motor and transmission by hand to see which one is stiff.

[Budget Appliance Repair]

Good chance it is your pump freezing up, wouldn't be that uncommon to see on one of this age especially if it's never been replaced.